This invention relates to high molecular weight benzobisazole copolymers containing cyclic phosphate ester groups.
Para-ordered, rigid-rod aromatic heterocyclic polymers, such as poly(p-phenylenebenzobisthiazole) (PBT), poly(p-phenylenebenzobisoxazole) (PBO) and poly(p-phenylenebenzobisimidazole) (PBI) are well known for their outstanding thermal, physical and chemical properties. The corresponding para-ordered, rigid-rod aromatic heterocyclic copolymers are also well known. These polymers and copolymers exhibit lyotropic behavior in strongly acidic solvents, such as methanesulfonic acid (MSA) or polyphosphoric acid (PPA) and can be readily spun into fibers or made into films which have exceptional tensile strength and modulus. The high thermooxidative stability of these fibers and films, together with their exceptional tensile properties and electrical non-conductivity make them obvious candidates for reinforcement in advanced composite materials.
The surface properties of high modulus materials have a strong impact on many if not most of their applications. The chemical structure and thermodynamic of polymer surfaces are important factors that determine may of their practical characteristics. Properties affected by polymer surface structure include adhesion, wettability friction, coatability and dyeability. Interfacial characteristics of reinforcing rigid-rod systems control adhesive strength of laminates and therefore the mechanical properties of composite materials.
Accordingly, it is an object of the present invention to provide a method for controlling the surface properties of rigid-rod aromatic heterocyclic copolymers.
Another object of the present invention is to provide novel rigid-rod aromatic heterocyclic copolymers.
Other objects and advantages of the invention will be apparent to those skilled in the art.